feat: gate NVIDIA IMEX enablement to GB200/GB300 NVLink systems

README.md

@@ -105,6 +105,16 @@ Default: `true`
 
 Type: `bool`
 
+### hpc_install_nvidia_imex
+
+Whether to install NVIDIA IMEX (`nvidia-imex`) and enable `nvidia-imex.service`.
+
+Note: "This role installs and enables the nvidia-imex service but does not start it immediately. The service is configured to launch at boot only on compatible multi-node NVLink switch-fabric systems, such as NVIDIA GB200 or GB300 (NVL72) racks."
+
+Default: `true`
+
+Type: `bool`
+
 ### hpc_install_rdma
 
 Whether to install the NVIDIA RDMA package.

defaults/main.yml

@@ -20,6 +20,7 @@ hpc_install_cuda_driver: true
 hpc_install_cuda_toolkit: true
 hpc_install_hpc_nvidia_nccl: true
 hpc_install_nvidia_fabric_manager: true
+hpc_install_nvidia_imex: true
 hpc_install_rdma: true
 hpc_enable_azure_persistent_rdma_naming: true
 hpc_install_system_openmpi: true

tasks/main.yml

@@ -527,6 +527,23 @@
         name: nvidia-fabricmanager
         enabled: true
 
+- name: Install/enable NVIDIA IMEX (NVLink multi-node runtime)
+  when:
+    - hpc_install_nvidia_imex
+    - ansible_facts["system_vendor"] == "Microsoft Corporation"
+  block:
+    - name: Install NVIDIA IMEX
+      package:
+        name: "{{ __hpc_nvidia_imex_package }}"
+        state: present
+        use: "{{ (__hpc_server_is_ostree | d(false)) |
+          ternary('ansible.posix.rhel_rpm_ostree', omit) }}"
+
+    - name: Enable NVIDIA IMEX service
+      systemd:
+        name: nvidia-imex.service
+        enabled: true
+
 - name: Install RDMA packages
   when: hpc_install_rdma
   block:

vars/main.yml

@@ -31,6 +31,7 @@ __hpc_cuda_driver_packages:
   - cuda-drivers
 __hpc_nvidia_fabric_manager_packages:
   - nvidia-fabric-manager
+__hpc_nvidia_imex_package: nvidia-imex
 __hpc_nvidia_container_toolkit_packages:
   - nvidia-container-toolkit
 __hpc_rdma_packages: